A communication system includes a collection of components that communicate, manipulate, and process information in a variety of ways. This system may support different access technologies, such as frame relay, circuit services, and new and evolving connection-based or connectionless services, that communicate information, such as data, voice, and video. Switches in the communication system employ hardware and software to route information generated by access technologies to an intended destination.
In such switches, different types of data cells are utilized to control switching connections. For example, a control cell can be used to establish communication on a connection or link. When a control cell of a particular type, such as a cell relating to an interim local management interface (ILMI), is processed at a switch control module, the switch control module (SCM) must be able to identify the port and link of origin for the control cell in order to establish communication. However, regardless of which link and processing port in a switch receives the cell of a particular type, the virtual path identification (VPI) field and the virtual channel identification (VCI) field of the control cell typically will be the same as the VPI field and VCI field, respectively, of other control cells of the same type. Thus, in some instances, the VPI/VCI identifier of a control cell cannot be used to identify a link and a port of origin for the control cell in a communication switch.